The present invention relates in a general way to earthmoving machinery.
Earthmovers include, for example, two types which are produced in very large numbers, namely, loaders and excavators.
Conventional loaders are self-propelled and have, at the front, a loading bucket which is usually about as wide as the machine itself. This bucket is filled by being pushed by the machine into the earth or into the materials to be loaded. Then it is raised, and the materials are carried by the machine to the transportation vehicles or to some other place, where they are unloaded.
Excavators have the function of digging in the ground. For this purpose, they have a tool that is generally mounted on a turntable which is usually of the full rotation type. This turntable in turn is borne by a self-propelled chassis.
These two functions are very different, and complementary at a give worksite. They therefore require two machines which likewise are different.
For small worksites, such a duplication of equipment is uneconomical. It should be possible for one machine to serve the two functions. With this in mind, loader-excavators have been built which have a loading bucket at the front and an excavator at the rear. But this combination of the two tools on a single chassis makes for a "bastard" machine and a complicated one, on which the excavation equipment handicaps the loading equipment. Furthermore, in a machine of this type, the excavator equipment cannot rotate fully and this rotation is even limited in many cases to about 180.degree. C., which seriously hampers the work.